The view constraint_column_usage
identifies all columns in the current database that are used by
some constraint. Only those columns are shown that are contained
in a table owned by a currently enabled role. For a check
constraint, this view identifies the columns that are used in the
check expression. For a foreign key constraint, this view
identifies the columns that the foreign key references. For a
unique or primary key constraint, this view identifies the
constrained columns.

Table 33-11. constraint_column_usage Columns

Name

Data Type

Description

table_catalog

sql_identifier

Name of the database that contains the table that
contains the column that is used by some constraint
(always the current database)

table_schema

sql_identifier

Name of the schema that contains the table that
contains the column that is used by some constraint

table_name

sql_identifier

Name of the table that contains the column that is
used by some constraint

column_name

sql_identifier

Name of the column that is used by some
constraint

constraint_catalog

sql_identifier

Name of the database that contains the constraint
(always the current database)